Investigation of astrophysical gamma-ray sources with a new detector concept
IDPASC Portugal - PHD Programme 2019
2019 / 2020
Giovanni La Mura
Instituto Superior Técnico
Laboratório de Instrumentação e Física Experimental de Partículas
Very-high-energy (VHE) gamma-rays are messengers of violent processes in the universe. In particular, their production is closely connected with the particle acceleration of the very-high-energy cosmic rays detected on Earth. VHE photons are thus key to understand the long-standing mystery of the mechanism by which cosmic rays are accelerated. Their intergalactic propagation across vast distances is sensitive to possible modifications of the structure of space-time on the Planck scale. Moreover, the detection of VHE gamma rays may also provide a clue to the nature of the dark matter (DM). In fact, weakly interacting massive particles (considered the most plausible form of DM) are expected to mutually annihilate, resulting in measurable signals, among them VHE gamma rays. Dark matter particles tend to accumulate at the centers of the galaxies. As such the center of our galaxy is a preferred spot to look for these DM signals. While most VHE gamma-ray detectors currently in operation are located in the northern hemisphere, several of the next-generation detectors are planned to be installed in the southern hemisphere, to have a privileged view of the galactic center. In this context LATTES (Large Area Telescope for Tracking Energetic Sources) is a project currently involving groups from Brazil, Italy, and Portugal (LIP), aiming to develop a next-generation gamma-ray detector to be installed in South America. The region of the Atacama Desert in northern Chile, at an altitude above 5000 meters, is one of the most promising sites. One of the biggest challenges to be addressed by LATTES is to bridge the gap between gamma-ray observations using satellites such as Fermi, sensitive up to several tens of GeV and the present and planned gamma ray ground-based experiments, which start to be sensitive at only several hundreds of GeV. By employing a hybrid detection technique and being deployed at high altitude, LATTES should be able to detect photons with energies as low as 100 GeV. The selected candidate will work on the assessment of LATTES science capabilities, namely on its ability to observe and extract information of extreme energy events such as binary neutron star mergers (which are associated to gamma-ray bursts and to the production of gravitational waves) or flares from the jets accelerated by massive black holes and fast rotating pulsars. This task will involve the modeling and interpretation of observational data and the development of analysis tools to improve the sensitivity of this future experiment.